High sulfur content fuel



Patented Mar. 23, 1954 2,673,145 HIGH SULFUR CONTENT FUEL William H. Chandler, to Shell Developmen Wood River, 11]., assignor t Company,

San Francisco,

Calif., a corporation of Delaware No Drawing. Application February 26, 1948,

Serial No.

8 Claims. 1

This invention relates to fuels which although having relatively high sulfur concentrations, are highly suitable for use in internal combustion engines, and particularly in diesel engines.

It has heretofore been observed that internal combustion engines, when operated on fuels having a relatively high sulfur content, exhibit much more corrosion on the metallic portions of the engine which contact the products of combustion of the fuel than when the sulfur content of the fuel is eliminated or substantially reduced; this is true irrespective of whether the sulfur is present in the free or combined state. This corrosion has been attributed to the acidic vapors formed on combustion of the sulfur-containing fuels, namely, sulfur dioxide and sulfur trioxide, and this is evidenced by the fact that the amount of corrosion increases with an increase in the sulfur content of the fuel. These gases, in the presence of water (which may be formed during fuel combustion and/or enter the engine through the air intake as the moisture normally present in the atmosphere), attack the metal parts exposed thereto. For example, corrosion is especially severe on the cylinder Walls and piston rings since, at the pressures developed therein over at least a portion of the power stroke, the Water is liquefied so that sulfur dioxide and trioxide dissolve therein to form sulfurous and/or sulfuric acid, which latter attack the exposed metal surfaces. The temperature of the cylinder also effects corrosion. Thus, engines operating at relatively low temperatures are more susceptible to corrosion since more moisture will condense at such lower temperatures. The thin oil film which may cover the metal parts affords only slight protection against the corrosive effects of the sulfur acids, which protection is completely inadequate whenever high sulfur content fuels are employed. However, the presence of sulfur in fuels has a beneficial effect in that the ignition properties of the fuel are improved thereby, i. e., fuel containing appreciable quantities of sulfur may be easily ignited in internal combustion engines.

'A further disadvantage of employing high sulfur content fuels in internal combustion engines is that the sulfur products of combustion also attack the lubricating oil, and especially oil additives, i. e., materials added to the oil to impart special properties or characteristics thereto, such as materials which may be added to oils as pour point depressants, oiliness, color, extreme pressure andviscosity index improvers, and oxidation inhibitors. Another disadvantage of high sulfur content fuels is the formation piston deposits in diesel engines.

Recognition of the overall adverse effect of the presence of sulfur and sulfur-containing compounds in fuels for internal combustion engines has led to widespread use of various processes directed to the removal of sulfur, which may be accomplished with more or less success by methods known to the art. However, these processes at best are expensive, commonly produce worthless by-products, and frequently have an adverse effect on the fuel itself.

An object of the present invention is to eliminate the necessity of removing sulfur from fuels having a relatively high sulfur content. Another object is to provide a high sulfur content fuel composition which is substantially non-corrosive to the metal parts of internal combustion engines, and which does not cause excessive engine deposits. A further object is to provide a new method of operation for combustion engines. A still further object is to provide a novel process for the production of power from high sulfur content fuels. Other objects and their achievement according to the present invention will be apparent from the specification.

It has now been discovered that the incorporation of certain compounds, a hereinafter described, in high sulfur content fuels eliminates, or at least materially reduces, the corrosive effects caused by the presence of sulfur, and substantially decreases the formation of engine deposits, and thus the incorporation of these materials in fuels eliminates the necessity of treating such fuels for the removal of the sulfur therefrom.

According to the quantity of a metallic inorganic salt, as'hereinafter defined, is incorporated in a high sulfur content fuel, it having been discovered that if such a material is incorported into a fuel having a high sulfur content, the corrosive effects of the sulfur oxides are substantially reduced and even substantially completely eliminated.

By employing high sulfur content fuels containing incorporated therein only a relatively very small amount of a metallic inorganic salt, in accordance with the present invention, the corrosion of the metal parts is practically completely eliminated, or is substantially reduced, and engine deposits are reduced so that the corrosion and deposition is comparable to that observed with a fuel containing low or negligible quantities of sulfur, and hence the necessity for employing expensive processes for removing sulfur from of heavy fuels is obviated, and the advantages of having present invention, a small sulfur present to improve the ignition properties of the fuel are preserved. A further significant advantage of the present invention is the prevention of oil depletion, i. e., the oil and the oil additives are not attacked by the products of combustion of the fuel, and therefore the oil retains the original. desired characteristics: and. special prop erties.

It is now evident that the present invention provides new fuel compositions, and a new-x method for operating combustion engines on high sulfur content fuels in a manner so-thatthein fiuence of sulfur on wear and. deposition-..isisube stantially eliminated. It is-,:-funther-::euident-thati the present invention provides a novel process-fun the production of power by burninga. high sulfur content fuel.

The advantages achieved tion, however, are limited high sulfur content fuels; covered, if the -.pr.esent:inorganic salts. be incorporated in fuels containing. relatively smallamounts.. of. .sulfur below. about 0.1%; no effect, either beneficialor adverse,.is observecl.. By the expression high ..sulfur.. content fuel-s, as used herein,..is meant those .fuels. which contain sulfur,- eitherinthe'free. orcombinedstate, to the extent of fronnabout 1 0.1% to about 5.0% by weight,v

by the present inventhoughveven. more-sulfur may be present, and

corporation with: thehighsulfun content fuels, .1

are generally Preferred according to the present. invention, the. metallic nitrates :and carbonates.

metallic. elements are .those. of. the: alkali or alkaline: earth groups-,- such. asclithium,v sodium, potassium, rubidium, cesium, calcium, strontium, and barium,..though the..salts .ofother base metalsmay. be used,- such? astitanium, vanadium,. chromium, magnesium,.cobalt, nickel, copper, zinc,.-.cadmium,

mercury,

bismuth. Bythaterm baseumetal, as, used herein, is. meant those. metals whose. hydroxides 8315i soluble .in. .water, orithe', metals that oxidize rapidly asopposed tocthe noble metals. Thus, for, example, the-.nitratesand.carbonatesof the alkali and alkaline v earth metals, suchas, of sodium,,. potassium,.. magnesium, barium nitrates. and. carbonatesillustrate. a .preferred group; of inorganic salts for usein the present-invention. Zinc, nitrate and. .carbonate illustrate. further preferred base. metal. salts. The nitrates are preferred.

The, inorganic salts of the. present invention may beincorporated inhigh sulfur content fuels by, any, convenient means. Some of the present salts, such ascalcium nitrate, have been found to be. sufficiently. solublein hydrocarbons, such as. diesel fuels. of high sulfur. content, so. that, a suificient .quantity. thereof may.. be.-. dissolved. .di.-.

rectly. therein to. realize the. advantages of the to the employmentaioff since, as has been disterm fuel,. as used The present "invention. is, a

about 0.2 %.:tov about 3 e.- g.., the; salts. of metals aluminum,., tin lead, antimony. and

calcium and.

present invention, and this method of incorporating an inorganic salt, as herein defined, constitutes a preferred method of preparing the novel fuel compositions of the present invention. Where desirable, solutizers, such as isopropyl alcohol may be used to assist in the production ofs. the -fuel composition:

A.-'-fur.the1: preferred "embodiment ofethe present invention is the injection of a solution, suspension, or dispersion, preferably a solution, of

the salt into the fuel or air stream during engine'bperation. For example, an alcoholic or aqueous.-solution-.of the salt may be injected into thewengine-iintake-air system, or into the fuel feedslineupriorztorinjection into the combustion chamber. Recourse may be had to a metering device to-regulate' the intermittent or continuous flow of the solution. When injection during enginesoperation is employed, the fuel compositions of the present invention are prepared at a points proximate .to their. ignition,,which;.may be. inathe. combustion. chamberitself, and..of course win. .such. instances. the. fuel compositions have a finite but short life; the existence I of the present fuel: composition,. in...liquid, vaporized or atomized form, for any, length. .of timeprior.

. tooactual: ignition: thereof, is.-.sufficient. to. result.

the exhaust stroke? instead .of forming deposits. Thus; for example; analkali metal nitrate may form. thenitrite,- or

operated in the. surprisingeadvantages of the: presentin vention.

While. it is not: desired tobe .limited .--by anytheoretical explanation of the mechanism of the. present. invention whereby I the presence of .-small= amounts-- of the present metallic. inorganicsalts.

eliminates; orat least -.materially reduces, theoorrosion-and deposition in: internal. combustion. engines: normally; observed when operated. on,

high sulfur content fue1s,- it is-believedthat the herein described-salts .-react with, or decompose.

under the conditions ofrcombustion, or other-.- wise form "-mater-ials which react with, the sulfur oxides-.or sulfur acids to for-m. non-corrosive.

materials, which materials. are. expelled: during-- the oxide, which then-reactswith-sulfur trioxide andwater (which is formedvby; the" combustion and/or enters the: combustion chamber with the. intakeair) ,,,or=

with-sulfurtrioxideper rosive metal 1 sulfate. while the reactants are in on min the 011 film covering partsiofthe engine.

The followingexamples serve to illustrate-the present'invention, which isnot to be-considered as limited thereby;

Example 1 se, to form the non-cor This reaction may: occurthegaseous phase, or' the various metal.

A standard. Fairbanks Morse diesel. engine was.

for 80 -hours..on audiesel .fuel contain-,- sulfur, and the amount 1 of ring. wear determined. The experiment .was. repeated. ex,-

cept thatv asolution. of calcium-nitrate -inisopropy1 alcohol was injected into the air intake system. at therateof. 0,6 cc. per minute the concentration of the: injection solution being:

such that I the: fuelconsumed contained 0.022 by; weight of calcium nitrate- (calculated as GEL-(NO?) 2 II-I20) The use of: calcium nitrate was;-found-to1-ree dllCBwtOt-Etl ring wear. by 50 It: was further;

observed that piston. cleanliness Twas-greatly im-1 proved when comparedwiththaresultsobtainediz,

when the inorganic salt 'washot employed.v

5. Example 2 Example 3 Example 2 was repeated except that the concentration of calcium nitrate was reduced to 0.0034% by weight (calculated as Ring wear reduction over that observed when no fuel additive was employed was 11%.

Example 4 Example 2 was repeated except that 0.0315% by weight of zinc nitrate (calculated as was incorporated in the fuel instead of calcium nitrate.

Ring wear reduction over that observed when no fuely additive was employed was 21%, and a substantial reduction of piston deposits was observed.

Example 5 A standard 1-71 General Motors diesel engine was operated for 80 hours on a diesel fuel containing 0.7% sulfur and the amount of ring wear and piston deposits determined. The experiment was repeated using the same fuel containing incorporated therein 0.022% by weight calcium nitrate (calculated as Ca(NO3)2-4H2O) and 1% by volume isopropyl alcohol.

Ring wear was reduced by 431% and piston deposits, particularly in the ring belt area, were substantially eliminated by the fuel additive.

Example 6 Example 5 was repeated except that Mg(NO3)2-6H2O in water solution was applied dropwise to the air induction system. Mg(NO3)2-6Hz0 was calculated to be 0.038% of the total fuel used.

Ring wear was reduced by 38%, and engine cleanliness was improved, intake port deposits being reduced by 35%.

Example 7 Example 8 Example 5 was repeated except that 0.015% of Mg (NO3)2-6H20 and 0.1% by volume of isopropyl alcohol was blended into 0.7% sulfur fuel, the resulting fuel composition being fed to the cylinders in the normal manner.

Ring wear was reduced by 21%, and engine improved, intake cleanliness was being reduced by v The optimum quantity of inorganic salt to be incorporated in the high sulfur content fuel will, of course, vary according to the quantity of sulfur in the fuel. As above stated, only very small quantities of the inorganic salts of the present invention need be added to the high sulfur content fuels in order to realize the advantages of the present invention. Thus, the preferred inorganic salts may be present in a quantity as low as about 0.003% by weight of the fuel, and corrosion will be substantially reduced. It is preferred, however, to employ from about 0.02% to about 0.5% by weight, though of course more may be employed where necessary or desirable.

As hereinbefore described and illustrated in the the incorporation of certain inorganic salts, as herein defined, in high sulfur content fuels reduces the corrosion attributable to the sulfur content so that the corrosion is comparable to that obtained with fuels containing only substantially negligible quantities of sulfur. The inorganic salts may also be introduced into the port deposits materials. Other modifications of the present invention will also be apparent to those skilled in the art.

The foregoing discussion has been directed largely to diesel engine operation, but the present invention is also applicable to other internal com- The invention claimed is:

1. A high sulfur content diesel fuel which oomprises a hydrocarbon diesel fuel containing from about 0.2% to about 3% sulfur, and from about 0.003% to about 0.5% by weight of hydrate-d calcium nitrate.

2. A high sulfur content fuel for internal combustion engines which comprises a hydrocarbon fuel containing from about 0.2% to about 3% sulfur and a minor 3. A high sulfur content fuel for internal combustion engines which comprises a hydrocarbon fuel containing from about 0.27 to about 3% sulfur and a minor amount sufficient to substantially reduce the engine wear caused by said sulfur of an inorganic alkaline earth metal nitrate salt.

4. A high sulfur content fuel for internal combustion engines which comprises a hydrocarbon fuel containing from about 0.2% to about 3% sulfur and a minor amount sufiicient to substantially reduce the engine Wear caused by said sulfur of a hydrated inorganic alkaline earth metal nitrate salt.

5. A high sulfur content fuel for internal combustion engines which comprises a hydrocarbon diesel fuel containing at least about 0.2% sulfur and a minor amount greater than about 0.003 weight per cent and sufiicient to substantially re- :duce thei engine Wear "caused :by :said :su-Iftir: :of'a

hydrated base metal inorganic nitrate.

' 6. The composition of =e1aim 5' wl'ierein "the hydrated'bas'e-metal inorganic nitnat'eishydrated izinc'gnitrate.

, ur =content 1 of-the hydrocarbon diesel fuel is 10 about 0."? ipenoentv WTLLIAMH. GHANDLER.

8 References Cited infitheflle of this patent UNITED I STATES PATENTS 

5. A HIGH SULFUR CONTENT FUEL FOR INTERNAL COMBUSTION ENGINES WHICH COMPRISES A HYDROCARBON DIESEL FUEL CONTAINING AT LEAST ABOUT 0.2% SULFUR AND A MINOR AMOUNT GREATER THAN ABOUT 0.003 WEIGHT PER CENT AND SUFFICIENT TO SUBSTANTIALLY REDUCE THE ENGINE WEAR CAUSED BY SAID SULFUR OF A HYDRATED BASE METAL INORGANIC NITRATE. 